The monuments were erected straight onto the substratum or with very shallow excavation. Some stone was quarried from local limestone and sandstone, some was recycled from nearby settlements and necropoli of earlier times. The materials vary widely: dressed stone blocks 1-1.5 m. long, partially dressed blocks up to 2.4 m. long, natural rock slabs with minimal dressing, old tombstones, and old building fragments. Most of the construction is dry stone; lime mortar is used sparingly.

The thirteen Jedars share many characteristics. There are also many similarities with much smaller Berber tombs called bazinas, which are common in the pre-Sahara zone. This shows that they represent indigenous Berber architecture in spite of their use of Roman architectural techniques and Mediterranean Christian iconography.

A square body, the largest being 46 m. on a side, and the smallest 11.55 m., with a height of up to 4 m. In some cases, the body is solid stonework, in the largest examples it contains funerary chambers.

A pyramidal top, which in all cases is very much ruined, but which must have been originally up to 13 m. high, constructed in many small steps (rise and tread about equal at around 0.2-0.25 m.). The top is mostly solid masonry, but in those jedars that contain funerary chambers, removable steps on one side conceal a passage leading down into the chambers, the ceilings of which may protrude up into the top.

Most, perhaps all, were surrounded by a courtyard, square except for an extension in the middle of the side facing east. In the larger ones this extension contains a small building modeled after the main monument. This building is believed to have been used for obtaining divinatory dreams by sleeping in the vicinity of the tomb.

Most if not all were further surrounded by a complex of low walls.

It is believed that the solid jedars that do not contain funerary chambers may cover a single tomb excavated into the bedrock.

The jedars of Jabal Lakhdar seem to have displayed a dedicatory inscription on one side of the top. This inscription was in Latin,[3] but not deeply engraved and hence in every case is now almost illegible; the inscribed blocks are also very damaged. Enough remains only to confirm that these were tombs, but not whose they were.[4] However, these jedars display an enormous range of stonecutters' marks, from isolated letters to partial names. Most of these are also Latin, some have been postulated to be Tifinagh.[5] There are a few unobtrusive Christian symbols, and a couple of roughly carved panels (apparently hunting scenes) similar to many ancient Lybico-Berber rock carvings.

The largest jedar at Ternaten is the only one in that group sufficiently intact to display epigraphy and iconography. It contained large well-executed polychrome murals (now almost completely weathered away) of religious scenes typical of Mediterranean Christian iconography of the 5th century or later,[6] indicating that the ruling class had by then become Christian. This jedar also contains many Latin inscriptions on recycled tombstones and other building material, dating from the time of Septimius Severus (202-203 CE) up to 494 CE. The source of this recycled material is not known with certainty, but there are several large ruins of cities and necropoli in the surrounding districts.[7]

The three jedars of Jabal Lakhdar are believed to be the oldest. Within this group, the relative chronology is now believed known, from study of the stonemasons' marks. The largest, with funerary chambers, known as Jedar A, is the oldest; very soon after, solid Jedar B was constructed by many of the same workmen. The last jedar, C, is believed to have been incomplete when it was very hurriedly finished[8] and its occupant interred, perhaps a generation later. Taking into account the unobtrusive nature of the Christian symbols, it is believed the occupants of these tombs were not themselves Christian but ruled over Christian subjects. Remains of a wooden coffin from Jedar B returned a C14 date of 410 ± 50 CE.[9] Calibrating the date on the OxCal system gives a range of 410 - 615 AD at 95.4% probability. A recent re-reading of the dedication from Jedar A has proposed a 4th-century date.[10]

The only jedar in the Ternaten group for which dating has been attempted is the largest, Jedar F. Because the latest recycled tombstone bears a date of 494, it may belong to the 6th or 7th century.[11] Unlike the Jabal Lakhdar monuments, its funerary chambers seem to have been built to hold more than one occupant, so it has been proposed that it is dynastic, with the smaller jedars surrounding it those of lesser nobility or rank.

The earliest known reference to the jedars is in the lost Tarikh of the 11th-century historian Ibrahim ar-Raqiq, in extracts preserved in the works of Ibn Khaldun and other later writers. ar-Raqiq relates that when the Fatimid caliph Ismail al-Mansur was conducting military operations in the Tiaret area, he was shown the jedars at Jabal Lakhdar and wanted to know what the dedicatory inscriptions said; he was given a fanciful translation that the monuments were built to celebrate a military victory by the Byzantine army of Justinian I. Although Ibn Khaldun lived in the area for a number of years, he made no other reference to the jedars.

Beginning in 1842, French military expeditions in the area noted the monuments, resulting in the first archaeological descriptions. Jedar A was opened in a very rough manner [12] in 1875 by antiquarians who failed to publish their research. In 1882, Professor La Blanchère from Algiers University published a detailed study on the jedars (mostly based on the previous excavations) and attempted to place them in historical context. His identification of them as belonging to the Berber king Massonas mentioned by the 6th-century historian Procopius is not supported today.

In the early 1940s, an anthropology student, Dr. Roffo, obtained permission to excavate. In pursuance of this, he used explosives to open Jedar B, from which he obtained a skeleton which was in a wooden coffin in a tomb excavated beneath the building; the same happened with one of the smaller jedars at Ternaten. The whereabouts of these skeletons is unknown (they may lie unrecognised in an Algerian museum) and Dr. Roffo, it is said, burnt most of his notes in a fit of pique after an argument with the Director of Antiquities (who had probably got wind of his methods of 'excavation').[13]

During the Algerian War of Independence the jedars were closed by the French military who filled in any entrances and laid mines in some places. After the war they were used by a shaman for quasi-Islamic fertility rituals until he was evicted by local authorities.

During the years 1968-70, an Algerian studying under Gabriel Camps at the University of Aix-Marseilles, Fatima Kadria Kadra, made the first archaeological study of the jedars to use systematic modern techniques. A book based on her thesis was published by Algiers University in 1983 and remains the definitive reference.[14] Attempts by Camps (1995) to attribute the tombs to known Berber kings such as Mastigas and Garmul are considered speculative.[15]

^Unless otherwise indicated, information has been taken from Kadra's (1983) publication, which is the most detailed archaeological work on the subject. See also LaPorte (2005) who supplies some information omitted from Kadra's work as published.

^Early researchers, including the influential archaeologist Stéphane Gsell (1901), claimed they were bilingual Latin and Greek, which is occasionally repeated even today (e.g. Alan Rushworth, 2004, "From Arzuges to Rustamids: State Formation and Regional Identity in the Pre-Saharan Zone" in A.H. Merrills (ed.) Vandals, Romans and Berbers: New Perspectives on Late Antique North Africa; Guy Halsall, 2007, Barbarian Migrations and the Roman West 376-568). Kadra (1983, e.g. p. 257 & 261; see also LaPorte, 2005, p. 365) has shown that almost all the so-called Greek is based on erroneously identified late forms of Latin letters, while the remainder is merely the combination of Greek alpha and omega used as a Christian symbol rather than as text.

^e.g. isolated words like egregius (eminent), duci (duke), filius (son) and matri (mother) can be made out

^How much time would have to elapse before a Christian ruler would rob Christian graves to build his own? has been asked in justification for these dates (Cadenat, 1957), but this does not take into account the often violent sectarianism of those times, viz. Arianism and Monophysitism.

^LaPorte (2005) p. 389-390. More recently the oldest of the jedars has been attributed by Lepelley & Salama (2006) to a 4th-century governor from Pontus in Asia Minor, but LaPorte considers this doubtful also.